Construction Handout



Construction Handout

Figuring Board Foot

Introduction:

Softwood lumber is usually purchased by specifying the number of pieces- thickness x width x length- in addition to the grade. Often, when no particular lengths are required, the thickness, width, and total number of linear feet (length in feet) are ordered. The length of the pieces then may vary and are called random lengths. Another method of purchasing softwood lumber is by specifying the thickness, width, and total number of board feet. Lumber purchased in this method may also contain random lengths.

Calculating Linear Feet:

When buying boards by linear feet, one must specify the thickness in inches and the width in inches of the boards to be purchased. To figure the linear feet simply add the total length of the boards together.

Example A:

The project calls for two 1x6x12’s, three 1x6x10, and one 1x6x6. The total linear feet would be 60 linear feet of 1x6’s. 12+12+10+10+10+6=60

Example B:

The 10’ partition wall requires eight 2x4x8’s and three 2x4x10’s. How many linear feet of 2x4’s are needed for the wall? 94 linear feet of 2x4’s are needed to complete the wall.

2x4x(8x 8)= 64

2x4x(10 x 3)=30

94

Calculating Board Feet:

A board foot is a measure of lumber. It is equivalent to a piece 1 inch thick, 12 inches wide and 1 foot long. To calculate the number of board feet, use the formula: number of pieces x thickness in inches x width in inches x length in feet / 12 = number of board feet. Remember that most wood sold is S4S. S4S refers to the fact that it has been dressed on four sides. A 2x4, nominal dimension, is really1.5”x3.5”, actual dimension, after it has been dressed. Always use nominal dimensions when figuring board feet.

Example C:

The project calls for four 1x6x2’s. How many board feet are needed?

4x1x6x2/12= 4 board feet.

Example D:

The 10’ partition wall requires eight 2x4x8’s and three 2x4x10’s. How many board feet of 2x4’s are needed for the wall?

8x2x4x8/12= 42.7

3x2x4x10= 20.0

62.7 board feet

Calculating Board Feet in Inches:

On smaller projects dimensions may be given in inches. Board feet can also be used in these cases when describing the lengths needed. To calculate the board feet when the length is in inches, use the formula: number of pieces x thickness in inches x width in inches x length in inches/ 144.

Example E:

The tool box requires two boards that are 1x6x10” and two boards that are 1x6x14”. How many board feet are used in the box?

2x1x6x10/144= 0.84

2x1x6x14/144= 1.17

2.01 bf

Example F:

The box requires for pieces that are 1x4x8” and two pieces that are 1x8x8”. How board feet are needed for the box.

4x1x4x8/144= 0.89

2x1x8x8/144= 0.89

1.78 bf

Practice:

1) 2x4

2) 2x14

3) 1x6x20

4) 1x8x7

5) 1x10x16

6) 9x2x4x12

7) 3x4x6x12

8) 13x6x6x12

9) 23x2x4x8

10) 19x2x6x12x4

11) 1x6x8/12

12) 2x4x10/12

13) 4x4x12/12

14) 20x2x4x8/12

15) 10x1x6x12/144

16) How many board feet are in one 2x6x10?

17) How many board feet are in three 2x4x12’s?

18) How many board feet are in one 4x6x12?

19) How many board feet are in one 1x6x10”?

20) How many board feet are in five 1x8x8”?

21) How many linear feet are in six 2x10x12’s?

22) How many linear feet are in four boards that are 1x6x10”?

23) The box requires for pieces that are 1x6x8” and two pieces that are 1x8x8”. How board feet are needed for the box.

24) The 20’ partition wall requires sixteen 2x4x8’s and six 2x4x10’s. How many board feet of 2x4’s are needed for the wall?

25) The 15’ partition wall requires thirteen 2x4x8’s and three 2x4x15’s. How many board feet of 2x4’s are needed for the wall?

26) How many board feet are in the project below? (Using 1x4’s)

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27) How many board feet are in the project below? (Thickness is ½”)

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28) How many board feet are in the project below?

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29) How many board feet are in the project below?

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30) How many board feet are in one 2x4x20? How board feet are actually in one 2x4x20?

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